The incidence of acute pancreatitis in UK has risen sharply over the past 40 years. Recent reports suggest that 56.5 per 100 000 of the population will suffer from AP annually; this figure is more than double the highest previous estimated incidence. In the majority of patients the condition is mild, but about 25% of patients suffer a severe attack and between 30 and 50% of these patients dies. The usual cause of death is multiple organ failure secondary to systemic leukocyte activation (mainly neutrophils), accompanied by the systemic inflammatory response syndrome (SIRS).